This large, beautiful Precious semi-crystal, harlequin-fire opal comes from the Rainbow Ridge mine of Virgin Valley in the state of Nevada.
Its mesmerizing multi-color with red, fire rivals the finest of any Australian opal. The translucent, semi-crystal blue-ish background actually makes the fire stand out next to skin. It has one small barely visible flaw on one side of the stone and a deep hard-to-see healed flaw partly across the bottom of the stone. It is borderline good-to-fine in normal grading, especially given its size. It is suitable for a pendant as well as display in a collection. The opal was mined from the perlite ash characteristic of much Virgin Valley, Nevada opal.
The Rainbow Ridge Mine is among the best known and most consistently productive of the Virgin Valley area of Nevada, and because of some unwanted unusual attention, has recently become a more heavily secured site. It is owned by a private extended family, with properties in Nevada and Arizona.
The opal is actually part of a fossilized twig or branch from a tree. Most of the Virgin Valley opal was formed when a volcanic eruption several millions of years ago covered a lake and its adjacent woods and marsh with a heavy layer of ash. The minerals and water combined to replace the wood to varying degrees, forming various types of opals. Some opal exactly resembles the original tree wood with colors and grain. Other opal is varying types of precious opal with varying sensitivity to cracking and crazing because of the high water content of the ash to this day surrounding the opal before it is mined and put into a dry environment of today's surrounding high semi-arid near-desert.
Opal is still being slowly formed between the ash and the water below. The marsh and lake are actually still beneath the ash and some parts of them are still visible on the surface and frequented by antelope and other animals. An active hot springs, with warm water natural pool near the main opal sites still provides wash and drinking water to campers. However, this is a remote area close to a mile above sea level with substantial snow and cold rains (about 10-12 inches a year) and rough dirt/mud roads. Mining is only done May-October, and sometimes does not begin until June.
